Demyelinating neuropathies or diseases can occur in both the central nervous system and peripheral nervous system. Such conditions include the well-known disease multiple sclerosis as well as Guillain-Barré Syndrome, chronic demyelinating polyradiculoneuropathy, diabetic mellitus or the hereditary sensory-motor neuropathies such as Charcot-Marie-Tooth disease, Friedrich's ataxia, porphyria, lipoprotein neuropathies, and familial amyloid neuropathies. Demyelination of nerve fibers results in a short-circuiting of nerve impulses and thus a slowing or blocking of transmission along the nerve fibers with associated disabling symptoms including spasticity, loss of motor strength, and painful dysaesthesias.
A well-known problem in treatment of neurological disorders is ineffective delivery of therapeutic agents to neurons and associated cells due to the blood-brain and blood-nerve barriers. Considerable development has gone into the development of drugs and delivery systems for the transport of pharmacologically active species across the blood-brain or blood-nerve barrier. Such attempts have included derivatizing a pharmacologically active species to include specific moieties recognized by various membrane receptors or alternatively to add lipophilic moieties.
To date, while these approaches have shown promise, surprisingly little therapeutic progress has been made with respect to demyelinating conditions or diseases. Thus, there exists a need for compositions including therapeutic quantities of an active species wherein the compositions are capable of crossing the blood-brain barrier or blood-nerve barrier in a manner that inhibits side effects associated with such treatments.